Over 360,000 Pennsylvanians served in the Union Army, more than any other Northern state except New York.[2] (Other states sent larger proportions of their population, but not larger numbers.) Beginning with President Lincoln's first call for troops and continuing throughout the war, Pennsylvania mustered 215 infantry regiments, as well as dozens of emergency militia regiments that were raised to repel threatened invasions in 1862 and 1863 by the Confederate States Army. Twenty-two cavalry regiments were also mustered, as well as dozens of light artillery batteries.

Most of the new Pennsylvania regiments were organized and trained at sprawling Camp Curtin near Harrisburg, as well as thousands of soldiers from other states. Other significant training sites were near Pittsburgh, Easton, Philadelphia and West Chester. Over 100 soldiers from Pennsylvania units would win the Medal of Honor for their actions during the conflict. Pennsylvania ranked first in the number of black soldiers (8,612) mustered into the Union Army, forming eleven regiments of U.S. Colored Troops.[11] Most of these trained at Camp William Penn, established in 1863 north of Philadelphia, the only camp used to train Colored Troops exclusively.[12]

The Bethlehem Iron Works produced railroad rails and armor plating for the U.S. Navy's ships. The largest producer of wrought iron artillery pieces for the Union army was the Phoenixville Iron Company in Chester County, which, at its peak, churned out fifty 3" Ordnance Rifles each week. Smaller facilities produced steel swords, rifles, pistols, tools, camp implements, tents and other items used by the Federal armies, making Pennsylvania one of the most important sources of government supplies during the war.[14]

The Philadelphia region was a major contributor to the war effort. The Frankford Arsenal was a vital source of small-arms, ammunition, artillery shells, and time fuses to the Federal army and state militia. The Philadelphia Navy Yard provided an important source of ships, sailors, and supplies for the United States Navy during the war. The vast majority of the coal used by the Navy for its warships and blockaders came from underground mines in several counties in northern Pennsylvania. The Satterlee Hospital and the Mower Hospital (both near Philadelphia) were significant military hospitals and rehabilitation centers, as was the York U.S. Army General Hospital.

On the other side of the state, Pittsburgh's heavy industry provided significant quantities of weapons and ammunition. The Fort Pitt Works near Pittsburgh made mammoth iron castings for giant siege howitzers and mortars, among the largest guns in the world. The foundry produced 1,193 guns (15 percent of the total U.S. wartime artillery production) and almost 200,000 artillery projectiles. Other prominent Pittsburgh area factories included Singer, Nimick and Co. (maker of 3" Ordnance rifles) and Smith, Park and Co., which produced more than 300,000 artillery projectiles. Pittsburgh industries collectively manufactured 10 percent of the total U.S. wartime production of artillery projectiles.

The U.S. Allegheny Arsenal was the primary military manufacturing facility for U.S. Army accouterments, as well as saddles and other cavalry equipment. In addition, the Allegheny Arsenal produced as many as 40,000 bullets and cartridges every day (more than 14 million per year), supplying between 5 and 10 percent of the Army's annual small arms ammunition requirements.

Five Ellet-class rams were converted from civilian towboats at Pittsburgh. In addition, four ironclads were built from the keel up: the USS Manayunk, Marietta, Sandusky, and Umpqua. Pittsburgh rolling mills supplied the armor for many of the ironclads that were built in New York and Philadelphia.

Throughout the war, Pennsylvania politics were dominated by Republicans under the capable leadership of Governor Andrew G. Curtin, a strong supporter of President Lincoln. The extreme southern tier of the state included a fair number of Copperheads, particularly in Fulton, Adams, and York counties.

One Pennsylvanian soldier spoke to a Confederate slave woman whose husband was whipped, and was appalled by what she had to tell him of slavery. He stated that "I thought I had hated slavery as much as possible before I came here, but here, where I can see some of its workings, I am more than ever convinced of the cruelty and inhumanity of the system."[19]

After the Battle of Antietam in fall of 1862, thirteen Union governors assembled in Altoona, Pennsylvania at the Loyal War Governors' Conference. This meeting was assembled by Governor Andrew G. Curtin and its purpose was to discuss strategy, troop quotas and the Union. The governors affirmed their support towards, as well as expressed their concerns regarding the war effort and the emancipation proclamation. They then traveled to Washington, DC, to meet Abraham Lincoln and relay their conclusions to him. A few weeks later, Lincoln removed General George B. McClellan from commanding the Army of the Potomac (about whom the governors had voiced their displeasure), and issued the Emancipation Proclamation.[20]

By late 1864, the majority of Pennsylvania voters had rallied around the president and supported his incumbency in the Presidential Election, giving Lincoln 296,292 votes or 51.6% of the ballots cast versus Maj. Gen. George B. McClellan's 277,443 votes (48.4%).[21]

While the war still raged, efforts were underway in Gettysburg to preserve portions of the battlefield for future generations as a tribute to those men who fought there. Pennsylvania also took steps to preserve and record the history of each regiment and unit raised in the state, as well as the muster rolls. In 1869, the official commonwealth historian Samuel Penniman Bates wrote the monumental five-volume History of the Pennsylvania Volunteers, 1861-1865 which remains the standard reference for the commonwealth's regimental histories and unit rosters.

The State Archives in Harrisburg preserves the military records of the state's emergency militia, as well as material on the state's volunteer regiments and batteries. It also houses microfilmed records of the damage claims from individuals in several counties, delineating losses of their personal property and possessions to the opposing armies during the Gettysburg Campaign. The Pennsylvania Capitol Preservation Committee maintains and preserves just under 400 of Pennsylvania's historic Civil War battle flags The State Museum of Pennsylvania houses an extensive general collection of Civil War artifacts, as well as Peter Rothermel's massive painting of the Battle of Gettysburg.

The National Civil War Museum in Harrisburg is one of the country's leading interpretive sites for the Civil War, and the Visitors Center at the Gettysburg Battlefield holds thousands of artifacts, including the largest collection of vintage Civil War weapons in Pennsylvania.[citation needed] Other Civil War-related museums are scattered throughout the state, as well as county archives and hundreds of memorials / monuments / historical markers. An impressive state-sponsored monument in the Gettysburg National Military Park honors Pennsylvania's soldiers and leaders.

Klein, Philip Shriver, A History of Pennsylvania. University Park, PA: Penn State University Press, 1980. ISBN0-271-01934-4.

McPherson, James M., Battle Cry of Freedom: The Civil War Era. New York: Oxford University Press, 1988.

U.S. War Department, The War of the Rebellion: A Compilation of the Official Records of the Union and Confederate Armies, 70 volumes in 4 series. Washington, D.C.: United States Government Printing Office, 1880-1901.

^United States. Army. Pennsylvania Infantry Regiment, 118th (1862-1865) (1888). History of the Corn Exchange Regiment, 118th Pennsylvania Volunteers, from Their First Engagement at Antietam to Appomattox: To which is Added a Record of Its Organization and a Complete Roster. Fully Illustrated with Maps, Portraits, and Over One Hundred Illustrations. J. L. Smith. pp. 652–.